1) Having no pity 2) Merciless 3) Pitiless 4) Pitiless, relentless 5) Ruthless 6) Showing no pity 7) Unmerciful 8) Unpitying 9) Without mercy or pity 1) Inexorable 2) Inhuman 3) Intolerant 4) Merciless 5) Pitiless 6) Ruthless 7) Unmerciful 8) Unpitying 9) Untiring 
• (a.) Being without remorse; having no pity; hence, destitute of sensibility; cruel; insensible to distress; merciless.
Re·morse'less adjective Being without remorse; having no pity; hence, destitute of sensibility; cruel; insensible to distress; merciless. ' Remorseless adversaries.' South. 'With remorseless cruelty.' Milton. Syn. -- Unpitying; pitiless; relentless; unrelenting; impl...
remorseless, remorselessness 1. Having no pity or compassion; merciless. 2. Unyielding; relentless. 3. Continuing without lessening in strength or intensity.
without mercy or pity